Are you asking yourself, “How much will a newsystem boiler with central heating cost me?

You’re definitely not the only one. Many homeowners find it confusing trying to work out the cost of a new central heating system with all the other important bits that go along with it (such as a new system boiler and radiators) because there’s just so many factors to consider.

Having installed many different central heating systems in homes across Edinburgh over the years, I can tell you right now that the overall cost can vary dramatically depending on the size and type of property you own, your current set-up, and the brand of boiler you choose.

For instance, there could be numerous reasons why you need a new central heating system with a new boiler: perhaps you own a large family home with no central heating, electric heating, or an old one-pipe system which is inadequate for your needs.

Regardless of the reason, I’m going to do my best to help you get a better idea of how much it’ll cost to install your new system boiler with gas central heating in your home – including some other key factors which may affect your overall costs.

Why choose a system boiler?

If you have a large home or a home that’s currently being altered to include extra bathrooms, you may not find a combi boiler an ideal solution, and choose to opt for a system boiler with unvented cylinder instead – giving you a stored capacity of hot water for multiple showers and baths.

Another reason you may choose a system boiler is if you already have a regular boiler fitted, with old fashioned pipework along with an existing expansion tank, but want to upgrade from an old one-pipe central heating system and install a more energy efficient boiler at the same time.

System boilers are very similar to regular boilers in that they work essentially the same way, the main difference being that they come with a pump and pressure vessel incorporated to pressurise the system. (So no feed and expansion tank required).

This one difference means that system boilers are generally cleaner, quieter and more efficient than regular boilers. The only thing to bear in mind is the extra upheaval that comes from installing or switching to a pressurised system – especially if you have concrete or sealed flooring!

TIP: You may also prefer a system boiler over a combi as it can heat both your hot water in the tank and you radiators at the same time, whereas combis always prioritise your hot water.

The average cost of a system boiler and gas central heating

Like I said above, the total price of your new gas central heating system with a system boiler can be a little hard to predict, as your overall costs will depend on the size and type of property you own – along with the type of heating you already have installed (if any).

Despite this, I can give you the typical average for a central heating heating system with one of our popular Worcester Bosch 30i system boilers, six radiators + pipework and valves will cost you around £4,500 – £4,800 incl. VAT.

Central heating with a system boiler and radiators is always slightly more expensive. This is because the boilers are much the same price as combis (a little cheaper), however there’s also more associated motorised valves, automatic by-pass along with the room thermostat, cylinder thermostat and wiring centre to consider.

This leads to added costs and extra labour when it comes time to install. I have also found recently that if the discerning energy-conscious customer goes for this option, they’re likely to fit a new hot water tank which is an extra cost.

So, compared to a combi boiler, we’re talking a few hundred pounds more expensive for your new system boiler, radiators and central heating.

What else can affect system boiler and central heating costs?

Because the price you can expect to pay for a new system boiler and central heating installation is very individual – I’d compare it to, say, buying a car or a tailored suit – unfortunately, I can’t give you a full cost breakdown without going to take a look at your home.

However, what I can do is give you an idea of some of the biggest factors affecting cost.

Brand of system boiler

There are many reputable boiler manufacturers making good value system boilers for large homes these days. From my own experience fitting many different brands of boilers over the years, models are only getting more reliable, however there are still some cheaper options out there.

I tend to be a tad on the biased side as I know from experience that premium brands do tend to offer the best value for money in terms of guarantees, but I’d tell you to invest in the best quality boiler you can find, with a long guarantee to cover you if anything goes wrong.

Trust me, it could save you a lot of money in the long run!

Choosing a new hot water cylinder

If you want to opt for a new hot water cylinder, the cost to remove an old low-pressure bare copper cylinder with no insulation in favour of a higher volume indirect one, supplied and fitted, usually costs somewhere between £450 – £850 (depending on size: 120 – 300 litres).

However, if we were to supply and fit a high pressure unvented hot water cylinder for practically unlimited hot water and amazing flow rates to your property, you could expect to pay as much as £1,040 – £1,980 (120 – 300 litres).

Type of radiators

As for radiators, most homeowners opt for white pressed steel, and maybe a chrome towel rail for the bathroom. You may instead want to go with column radiators or coloured radiators, which can be more expensive.

Recently, I’ve helped some homeowners who just weren’t sure if designer radiators were worth the extra expense, by pricing up the standard Stelrad radiators and allowing them to check the prices of designer radiators before getting back to me with their final choice.

Type of flooring

Last but not least, if you currently have laminate flooring or sealed flooring, you may need to think about replacing it if there’s no other way for an engineer to access the area underneath. Again if you have solid stone floors you may have to have the floors cut to install pipes. Especially if running pipes along the surface just doesn’t appeal.

Sadly, this will mean more upheaval and expense, but the end result will leave you with a much more professional job with concealed pipework.

Unfortunately, polished flooring will never go back the same way as it was, so you may want to consider getting a specialist contractor in to lift and relay it. Sorry about that.

Advice from an experienced engineer

I’d recommend thoroughly doing your homework as well as getting around 2-3 fully inclusive fixed price quotes for your property, so you’ll know exactly how much your new system boiler and gas central heating installation will cost before agreeing to any work.

If there’s really not much price difference in the quotes you receive, I’d always go with the most knowledgeable engineer for the job – and preferably one that’s happy to listen to you and give you his/her advice on what they think the best solution is for your home.

Ask about locating your new system boiler and cylinder close to each other to prevent heat loss. (Heat can be lost when traveling long distances between the boiler and cylinder, wasting heat along the way). Ask about the size of the existing cylinder against a new larger capacity cylinder. You may also want to check about smart energy efficiency controls to complement the new system.

I recently had a job where we were awarded the contract on our sound advice. The previous engineer never mentioned upgrading the cylinder whilst designing the new system boiler and radiators, despite the fact the existing cylinder was too small for the now-extended house.

Upgrading the cylinder was very straightforward and easy to do whilst installing the new boiler and radiators.

Also, you’ll also really want to know your chosen Gas Safe registered installers are very experienced at installing full gas central heating systems in your type of property. For example, a company that specialises in installing system boilers in large homes would be ideal for you.

You’ll probably also feel at ease knowing the engineers are comfortable doing your type of project and will respect your home.

TIP: It’s also worth discussing your needs for hot water (filling baths and running showers) as you may wish to pay a little extra for a system boiler with a higher output and better flow rate!


I hope you’ve enjoyed reading, and hopefully by now you should have a rough idea of how much you can expect to pay for your new system boiler and gas central heating for your large family home.

I only wish I could have been of more help, but without a visit to your home, it’s impossible to tell exactly what the work will involve – which is why you should always request a home visit and fixed price quote.

However, what I can offer to do is answer any more specific questions you might have in the comments – I’ll be happy to help and I’ll get back to you when I can!